Verb Variability and Morphosyntactic Priming With Typically Developing 2- and 3-Year-Olds.

Purpose: This study was specifically designed to examine how verb variability and verb overlap in a morphosyntactic priming task affect typically developing children's use and generalization of auxiliary IS. Method: Forty typically developing 2- to 3-year-old native English-speaking children with inconsistent auxiliary IS production were primed with 24 present progressive auxiliary IS sentences. Half of the children heard auxiliary IS primes with 24 unique verbs (high variability). The other half heard auxiliary IS primes with only 6 verbs, repeated 4 times each (low variability). In addition, half of the children heard prime-target pairs with overlapping verbs (lexical boost), whereas the other half heard prime-target pairs with nonoverlapping verbs (no lexical boost). To assess use and generalization of the targeted structure to untrained verbs, all children described probe items at baseline and 5 min and 24 hr after the priming task. Results: Children in the high variability group demonstrated strong priming effects during the task and increased auxiliary IS production compared with baseline performance 5 min and 24 hr after the priming task, suggesting learning and generalization of the primed structure. Children in the low variability group showed no significant increases in auxiliary IS production and fell significantly below the high variability group in the 24-hr posttest. Verb overlap did not boost priming effects during the priming task or in posttest probes. Conclusions: Typically developing children do indeed make use of lexical variability in their linguistic input to help them extract and generalize abstract grammatical rules. They can do this quite quickly, with relatively stable, robust learning occurring after a single optimally variable input session. With reduced variability, learning does not occur.

Past Tense Production in Children With and Without Specific Language Impairment Across Germanic Languages: A Meta-Analysis.

PURPOSE: This study examined the extent to which children with specific language impairment (SLI) across Germanic languages differ from their typically developing (TD) peers in the use of past tense morphology. METHOD: A systematic literature search identified empirical studies examining regular and/or irregular past tense production by English and non-English Germanic-speaking children with SLI and their TD peers. Data from qualifying studies were extracted and converted to Hedges's g effect sizes. RESULTS: Seventeen English and 8 non-English Germanic studies met inclusionary criteria. Comparing children with SLI and their TD age-matched (TDA) peers resulted in large combined effect sizes for English and non-English Germanic regular and irregular past tense production. Comparisons between children with SLI and their TD younger (TDY) peers also revealed large combined effect sizes for English and non-English Germanic regular past tense production. Effect sizes for studies comparing SLI and TDY irregular past tense production were large for non-English Germanic-speaking children and moderate for English-speaking children. CONCLUSIONS: Results suggest that children with SLI across Germanic languages do indeed have more difficulty marking verbs for past tense than TDA and TDY peers. The findings suggest that the potential value of past tense production as a clinical marker of SLI may well extend beyond English.